DETECTION OF PLASMA ALPHA-GRANULE MEMBRANE-PROTEIN GMP-140 USING RADIOLABELED MONOCLONAL-ANTIBODIES IN THROMBOTIC DISEASES

There is an assumption that platelet activation an endothelium damage play a critical role in the pathogenesis of thrombotic disorders. A ra dioimmunoassay based on using two monoclonal antibodies (MAbs) to diff erent epitopes of ct-granule membrane protein (GMP-140) was used to de termine whether plasma GMP-140 can be detected in patients suffering f rom acute myocardial infarction (AMI) or cerebral thrombosis and in pa tients during cardiopulmonary bypass (CPB). MAb SZ-51 was used as a so lid phase, and I-125-labeled MAb S12 was used as a fluid phase. The as say is so sensitive that it can detect as little as 1 ng/ml of purifie d GMP-140. The intra- and interassay coefficients of variation were 4. 2% (n = 5) and 7.1 % (n = 8), respectively. The concentration of plasm a GMP-140 was found to be 10.0 +/- 4.5 ng/ml (mean +/- SD, n = 20) in normal subjects. Ten patients undergoing CPB demonstrated a transient increase in the concentration of plasma GMP-140, especially at 2 h aft er CPB, and the plasma GMP-140 level was inversely correlated with the decreased platelet counts during bypass (r = -0.81, p < 0.01). It was found that the concentration of plasma GMP-140 increased significantl y after AMI. Plasma GMP-140 reached the peak within 3 days and changed with the process of AMI (n = 16) patients. The concentration of plasm a GMP-140 increased significantly in patients with cerebral thrombosis in the acute phase but not after relief. These data considered togeth er suggest that plasma GMP-140 can be reliably detected by radioimmuno assay based on using two MAbs which can recognize the different epitop es of GMP-140, and plasma GMP-140 may provide a useful marker for thro mbosis and some thrombotic diseases.